Switching company while performing data intensive tasks can cause records to get updated in the wrong company: https://mbs.microsoft.com/customersource/support/selfsupport/hottopics/ht_ax2009_duplicatecompanyissue.htm.htm?printpage=false There is a kernel hotfix available to address this issue, for both AX2009 SP1 and AX2009 RTM, it will be available under KB974507 and can be obtained by contacting Microsoft Support.